Monodispersed LaF 3 nanocrystals: shape-controllable synthesis, excitation-power-dependent multi-color tuning and intense near-infrared upconversion emission

In this study, monodispersed and high-quality hexagonal phase LaF 3 nanocrystals with different shapes and sizes were synthesized by a solvothermal method using oleic acid as the stabilizing agent. The as-prepared LaF 3 nanocrystals were characterized by transmission electron microscopy (TEM), x-ray diffraction (XRD), and analysis of the upconversion spectra. The TEM results reveal that the samples present high uniformity and monodispersity and are self-assembled into a two-dimensional ordered array. Moreover, the shape, size and structure of the nanocrystals can be readily tuned by adjusting the NaF content. With increasing content of NaF, the shape of the LaF 3 nanocrystals changed from particle to rod and the size gradually increased. More importantly, high NaF content favors the formation of one-dimensional nanorods. High Y b 3+ and Er 3+ content is beneficial to synthesizing the hexagonal phase of NaLaF 4 nanocrysta...

Ling Rao, Wei Lu, Guozhong Ren, Haibo Wang, Zhigao Yi, Hongrong Liu and Songjun Zeng

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